摘要
为探究镉胁迫对大薸(Pistia stratiotes)生长的影响及其体内镉积累与分布特征,用不同镉浓度(0、10、25、50、75、100μmol·L^(-1))的营养液处理大薸18 d,测定植株生物量、生长形态及其体内镉含量,并分析叶片中镉的亚细胞分布和化学形态。结果表明:随着镉浓度的增加,大薸生物量、冠径、叶片数、分株数和镉富集系数均呈降低趋势,地上部镉含量和镉转移系数呈上升趋势,地下部镉含量、总镉含量、单株富集量呈先上升后降低的趋势。在各处理下,大薸地下部镉含量均大于地上部。当镉浓度>10μmol·L^(-1)时,大薸叶片细胞壁组分镉的占比最大(42.61%~46.91%),其次是细胞器组分(27.04%~39.72%)和可溶性组分(17.68%~26.06%)。细胞壁和可溶性组分镉的占比随着镉浓度的增加呈上升趋势,细胞器组分则呈下降趋势。大薸叶片中镉主要以醋酸提取态为主(35.00%~59.06%),其次是氯化钠提取态(16.72%~26.45%)和水提取态(7.77%~33.22%)。研究表明:大薸通过根系固持、细胞壁固定和液泡区室化避免严重镉胁迫损伤,通过醋酸提取态贮藏降低镉毒性和移动性;10~100μmol·L^(-1)镉处理18 d后,大薸可维持较高的镉富集量和较低的生物量,在进行镉污染水体生态修复的同时避免因其快速生长而引起水体二次污染。
Pistia stratiotes plants were treated with different cadmium concentrations(0,10,25,50,75μmol·L^(-1),and 100μmol·L^(-1))in a nutrient solution for 18 days to explore the effects of cadmium stress on the growth and cadmium accumulation and distribution characteristics of P.stratiotes.The biomass,growth form,and cadmium content were determined,and the subcellular distribution and chemical forms of cadmium in leaves were analyzed.The results showed that as the cadmium concentration increased,the biomass,canopy diameter,leaf and tillering number,and cadmium bioconcentration factor gradually decreased.The overground cadmium content and cadmium transfer coefficient increased,while the underground and total cadmium content as well as the number of individual plants first increased and then decreased.The cadmium content underground was higher than that overground under each treatment.When the cadmium concentration>10μmol·L^(-1),the cadmium content of the cell wall was the highest(42.61%~46.91%),followed by that in the organelles(27.04%~39.72%)and soluble(17.68%~26.06%)in leaves.The cadmium ratios in the cell wall and soluble increased gradually with the increase of cadmium concentration;however,those in the organelles showed a downward trend.Cadmium was mainly extracted by acetic acid(35.00%~59.06%),followed by sodium chloride(16.72%~26.45%)and water(7.77%~33.22%)in leaves.In conclusion,P.stratiotes avoided serious cadmium stress damage through root fixation,cell wall fixation,and vacuolar compartmentalization,and reduced cadmium toxicity and mobility through acetic acid extraction state storage.After 10~100μmol·L^(-1)cadmium treatment for 18 days,P.stratiotes could maintain higher cadmium enrichment and lower biomass to avoid secondary pollution caused by their rapid growth during the ecological restoration of cadmium-polluted waters.
作者
黄蕊
辛建攀
田如男
HUANG Rui;XIN Jianpan;TIAN Runan(College of Landscape Architecture,Nanjing Forestry University,Nanjing 210037,China)
出处
《农业环境科学学报》
CAS
CSCD
北大核心
2022年第9期2033-2042,共10页
Journal of Agro-Environment Science
基金
国家自然科学基金项目(30972408)
江苏高校优势学科建设工程资金项目(PAPD)。
关键词
镉
大薸
亚细胞分布
化学形态
cadmium
Pistia stratiotes
subcellular distribution
chemical form
